1. Field of the Invention
The present invention generally relates to a by-pass rectifier element and a terminal housing for solar battery modules employing a by-pass rectifier element. In particular, the invention relates to a by-pass rectifier element configured such that it can withstand stresses caused by swelling or shrinkage of structural materials, when used under severe climatic conditions.
2. Description of Related Art
As shown in FIGS. 2 and 6, a known by-pass diode 100 includes a rectifier laminate 101 essentially formed by laminating, from bottom to top, a base lead plate 103, a cathode electrode 101a, an n-type domain layer 101b, a p-type domain layer 101c, an anode electrode 101d, and a top lead plate 105. The base lead plate 103 has a rectangular form, one end portion of which is connected to the cathode electrode 101a at the bottom of the rectifier laminate 101 by soldering. The top lead plate 105 includes a rectangular portion 105a and a head portion 105b which extends outward from one side end of the rectangular portion and is connected to the anode electrode 101d at the top of the rectifier laminate 101 by soldering. Further, the top lead plate 105 and the base lead plate 103 are arranged parallel to each other, but extend in opposite directions from the rectifier laminate 101 (FIG. 2).
The above by-pass diode is incorporated into a terminal housing for solar battery modules 110 as shown in FIG. 1. To mount such a terminal housing, there is first provided a housing 111, made of e.g. a synthetic resin, including a base and sidewalls, the top being left open. The base carries, in parallel, e.g. four lead-frame receiver terminals 113a, 113b, 113c and 113d. A plurality of by-pass diodes 100 are intercalated between the lead-frame receiver terminals 113a to 113d, such that the base lead plate 103 and top lead plate 105 of each by-pass diode are connected respectively to the adjacent lead-frame receiver terminal 113a, 113b, 113c or 113d and soldered thereto. The receiver terminals 113a and 113d located at both ends of the housing 111 are respectively connected, by clamping, to corresponding module-linking cables 117a and 117d, which are led into the housing 111 from outside through two fitting holes 115a and 115d formed in a sidewall of the housing 111.
The base of the housing 111 is further provided with path holes 121a, 121b, 121c and 121d, respectively formed adjacent to the corresponding lead-frame receiver terminals 113a to 113d. 
The housing 111 is fitted to a solar battery module (not shown in figures), from which are led out a positive-electrode lead frame 119a and a negative-electrode lead frame 119d. The positive- and negative-electrode lead frames 119a and 119d are led into the housing 111 through e.g. respective ones of the path holes 121a and 121d and connected to the lead-frame receiver terminals 113a and 113d. The housing 111 is then filled with e.g. silicone (not shown in figures).
As described above, the by-pass diodes 100 are placed in a housing 111 made of e.g. synthetic resin and embedded therein with e.g. silicone. However, the housing 111 and silicone swell and shrink repeatedly, each time they are used under severe conditions caused e.g. by steep temperature changes. Repeated swelling and shrinking imparts excessive stresses to the portions of the by-pass diodes 100 linking the base and top lead plates 103 and 105 to the rectifier laminate 101. The link portions can then become detached or the rectifier laminate can become delaminated, thereby causing an electrical break.
Such a phenomenon frequently occurs when a plurality of by-pass diodes 100 are mounted in series.
An object of the present invention is therefore to provide stress-resistant by-pass rectifier elements, which may be used in a terminal housing for solar battery modules. In the rectifier elements of the present invention, the portions thereof linking the lead plates to the rectifier laminate cannot be delaminated or detached, even when the elements are used repeatedly under severe climatic conditions.
Another object of the present invention is to provide a connector housing for solar battery modules incorporating the by-pass rectifier element of the present invention.
To this end, according to one aspect of the present invention, there is provided a by-pass rectifier element including a rectifier laminate having the form of a chip with first and second faces. The by-pass rectifier element further includes a first lead plate and a second lead plate, each having a longitudinal extension with an end portion, the end portions being arranged respectively on the first face and second face of the rectifier laminate. The first lead plate and the second lead plate extend in parallel in opposite directions, respectively from the first face and second face of the rectifier laminate. In the structure of the present invention, the first lead plate is thinner than the second lead plate.
Preferably, the first lead plate includes a zone adjacent to the end portion, and the zone is provided with slits notched alternately in the direction perpendicular to the longitudinal extension along which the first lead plate extends.
Further, at least one of the first and second lead plates includes a rectangular body portion including short sides and long sides, and the end portion of at least one of the first and second lead plates is formed into a head portion extending from one of the short sides of the rectangular body.
The head portion may include a neck portion having a reduced width with respect to the head portion.
Further, the short side of the rectangular body portion may be grooved at both sides of the neck portion along the long side of the rectangular body.
The invention also relates to a by-pass rectifier element including a rectifier laminate having the form of a chip with first and second faces. The by-pass rectifier element further includes a first lead strip and a second lead strip, each having an end portion respectively arranged on the first face and second face of the rectifier laminate. The first lead strip and the second lead strip extend in parallel along opposite directions, respectively from the first face and second face of the rectifier laminate.
At least one of the first and second lead strips may include an elongated rectangular body portion including short sides and long sides.
The end portion of the at least one of the first and second lead strips is formed into a head portion extending from one of the short sides of the elongated rectangular body portion, and the elongated rectangular body portion has a width narrower than that of the head portion and extends therefrom.
Preferably, the first lead strip is thinner than the second lead strip.
The invention further relates to a terminal housing incorporating a by-pass rectifier element for solar battery modules. The by-pass rectifier element includes a rectifier laminate having the form of a chip with first and second faces. The by-pass rectifier element further includes a first lead plate and a second lead plate, each having an end portion arranged on the first face and second face of the rectifier laminate, respectively. The first lead plate and the second lead plate extend in parallel along opposite directions, respectively, from the first face and second face of the rectifier laminate, wherein the first lead plate is thinner than the second lead plate. The housing further includes a container mounted into the solar battery module; a plurality of lead-frame receiver terminals arranged in the container and connected to positive and negative electrode lead frames extending from the solar battery module; a pair of module-linking cables for a power source, one end of which is connected to one of the lead-frame receiver terminals, and the other end of which is drawn towards the outside of the container; and wherein each of the first and second lead plates is intercalated or positioned between corresponding lead-frame receiver terminals so that it is electrically connected thereto.
The invention also relates to a terminal housing incorporating a by-pass rectifier element for solar battery modules. The by-pass rectifier element includes a rectifier laminate having the form of a chip with first and second faces. The by-pass rectifier element further includes a first lead strip and a second lead strip each having an end portion arranged on the first face and second face of the rectifier laminate, respectively, the first lead strip and the second lead strip extending in parallel along opposite directions, respectively, from the first face and second face of the rectifier laminate.
Further, at least one of the first and second lead strips includes an elongated rectangular body portion including short sides and long sides; an end portion of the at least one of the first and second lead strips is formed into a head portion extending from one of the short sides of the elongated rectangular body portion, the elongated rectangular body portion having a width narrower than that of the head portion and extending therefrom.
The terminal housing further includes: a container mounted into the solar battery module; a plurality of lead-frame receiver terminals arranged in the container and connected to positive and negative electrode lead frames extending from the solar battery module; a pair of module-linking cables for a power source, one end of which is connected to one of the lead-frame receiver terminals, and the other end of which is positioned outside of the container; and wherein each of the first and second lead strips is intercalated or positioned between corresponding lead-frame receiver terminals so that it is electrically connected thereto.
Typically, the first lead strip is thinner than the second lead strip.